The radiochemistry core provides the radiopharmaceuticals, radiopharmaceutical quality control, metabolite analysis and regulatory documentation required by the projects to fulfill the goals of the research described in this application. The specific aims are to produce 11C, 18F, 15O and 124I, and to use these radionuclides to make the radiopharmaceuticals: 2-[11C]thymidine; [11C]-verapamil; [11C]-meta-hydroxyephedrine; [11C]-carbon dioxide; [18F]-2-fluoro-2-deoxy-D-glucose; [18F]-fluoromisonidazole; [18F]-fluorothymidine; [18F]-fluoroannexin V; 16-alpha-[18F]-fluoroestradiol; [15O]-water and injectable [124I]-iodide. Robot-assisted and remotely operated syntheses are used to make procedures more convenient and to keep radiation exposure to the chemists as low as reasonably achievable. The radiochemists are responsible for assuring the radiochemical purity and pharmaceutical quality of all products for in vivo studies and for compliance with all regulations regarding radiation and pharmaceutical safety.